#include<bits/stdc++.h>
using namespace std;

int main() {
	pair<int, char> h[3];
	for(int i = 0; i < 3; ++i) {
		cin >> h[i].first;
		h[i].second = (char)('A' + i);
	}
	sort(h, h + 3);
	reverse(h, h + 3);
	for(auto e : h) {
		cout << e.second << '\n';
	}
	return 0;
}